duete; see due, ty 2 ]. syn: duty, obligation refer to something a person feels bound to do. A duty often applies to what a person performs in fulfillment of the permanent dictates of conscience, piety, right, or law: one's duty to tell the truth; a parent's duty to raise children properly.
Mutations in the RB1 gene are responsible for most cases of retinoblastoma. RB1 is a tumor suppressor gene, which means that it normally regulates cell growth and keeps cells from dividing too rapidly or in an uncontrolled way.
Scientists are still trying to determine the exact cause of macular pucker (scar tissue on the retina). While not specific causes of the condition, vitreous pulling and certain eye conditions -- including inflammation of the eye and vitreous detachment -- put people at a greater risk for developing a macular pucker. Other potential macular pucker causes include diabetic retinopathy and eye surgery.